35018 British India Line

That steam leak still not been tackled? It was leaking at that spot on the RH cylinder a month ago... doesn't quite sound right either, not the crisp chatter of 35028. Suspect it'll be a while yet before 35018 is storming Shap or the Devon banks...

 

Except when I compare the two videos (from the beginning of July and from last week) if anything it's got worse, it's difficult to see from the vids but the one in July looks mainly from the valve glands, but in the most recent run is that a blow I can see from the piston gland? More mileage should help these glands "bed in" - unless of course there are other blows we can't see?

 

This can depend on how she's being driven i.e at what cutoff. These locos (or so I have been told by a credible source) don't like being pulled in tight like an LMS Pacific.

 

I would imagine the drivers who have driven 35018 on test, have also driven 34046 on the mainline, so should know how to best drive a rebuilt, Looks like 35018 will need further adjustments yet , whats yet to be seen if West Coast are happy enough with her yet to risk her on any tours or if its further test runs, and an entry into service later this year/ early next year .

 

I would think most of the northern WCRC drivers would not have driven 34046 it is more likely to be the likes of Pete Roberts or Bob Baines down South.

 

While that's reasonably widely accepted, I've always found it slightly strange. I mean, there are no obvious reasons why an MN shouldn't like being notched up - they have large, long lap valves with generous steam pipes and reasonable superheat - and yet it's almost certainly the case; they were hardly ever run at less than 20% as far as I can tell. The LNER Pacifics were certainly routinely notched up shorter than that, at least from the A3s onwards.

It's not as if the Southern was a hotbed of long cut off and part open regulator; Drummond was a fervent advocate of the wide open regulator and short cut off on the LSWR, where it stuck, and it was shown to be the most efficient way of working the King Arthurs when they spread to other sections. I believe Stewarts Lane crews took a bit of persuading to begin with, but after some comparative trials between them and Nine Elms men on each others workings the penny dropped.

I do remember seeing a clip of video from back in the '90s, in which a main line driver commented that 34027 was more tolerant of being notched up than 35028 - if you pulled 35028 up too far she wouldn't steam, whereas 34027 would run. I wonder if Bulleid's famous one-size-fits-all implementation of the Lemaitre had something to do with it - better suited to the Nelsons and West Countries than the MNs, unless they were being worked harder. The other option is some quirk of the cylinder design and valve events. If anyone has a better idea of why this should be I'd be glad to hear it.

 

Given that the Nelson (for which Bulleid originally designed the Lemaître-type blastpipe) has a swept cylinder volume of 12.87 cubic feet, you'd have thought the 10.6 cu.ft. MN would like it more than the 8.775 cu.ft. WC/BB!

Do non-rebuilt WC/BBs take a finer cutoff better than their rebuilt bastardised ex-siblings?

 

More volume yes, but in eight beats of size closer to the WC/BB. The boiler is probably a closer match in size too.

 

Doubt very much that Mr B had anything to do with the design of his blast pipes beyond asking for drawings from his French counterparts, who would have supplied these from a Loco of roughly similar size.

 

It is the Bulleid-Lemaitre design that is in error. The blastpipe is too far removed from the chimney which was in its original form also plainly wrong.
Curiously the Ell modification of that chimney did not really help since the Rugby reports show a poorer performance in comparison.
I would like to improve along the line of the Lemaitre!
Kind regards
Jos Koopmans

 

Jos, could fitting a Lempor be an improvement? Or have things progressed beyond even Lempor?

 

Its not about the brand, its about the fit ...
But there is a lot of contemporary practical experience around the fitting of Lempor.

 

Haven't we been here in the not so distant past?

 

I have had discussions with MN/BB/WC owners. Most of them reject a longer inside chimney, so a Lempor is out. As far as I am aware most of them are happy with the present front end. However it could easily be improved upon retaining the principles of a Bulleid Lemaitre! For what my calculations are worth, the calculated performance of the present front has the largest difference with the measurements of all 550 Rugby tests.
Kind regards
Jos Koopmans

 

Well, in some ways the owner's viewpoint is understandable, after all when listing classes that don't steam the Bulleids would hardly be high on the list. But I am curious about your findings; is the current setup notably poor at lower flow rates or something? Clearly it functions adequately at making steam when the loco is working hard, but I can see that at short cutoffs the energy in the exhaust steam (and indeed the amount) will be lower than if the loco is throttled to achieve a similar power output at longer cutoff.

 

Whilst some of their best work was at 20-22% cut off I can confirm that the rebuilds ran fine with 15% cut off and speed in the seventies. Evidence from my footplate rides eg April 1964 Soton to Waterloo in just over 79 minutes with easy running in from Basingstoke due to being early.

 

There was some YouTube footage of a preserved rebuilt (WC iirc) at slow speed and you can actually see exhaust being drawn back in around the periphery of the chimney.

 

Thanks Don, it's good to hear this sort of thing from eyewitnesses. As I said in my original post, the general belief that MNs don't like being notched up always seemed hard to explain in a technical sense. I suppose a driver would be more inclined to use the shorter end of the cutoff scale on a rebuild than an original, less chance of the gear going past mid...

 

Regarding the notching, the original ones have the chain driven version, rebuilt ones Walschaert which could explain differences. As for the front end, Ell replaced the bottom part of the original chimney, which was a large cone entrance, into a longer chimney with a rounded entrance. So the length/diameter ratio of both versions is plainly different. Secondly the distance of the orifices to the throat is much larger than Ell thought useful, so the jets entrain all combustion products possible and little is left to the suction of the chimney. Thirdly the chimney is rather wide, performs badly and gives a very low exit velocity which the head wind loves to master! I would suggest a proper distance for the orifices, there could be seven instead of five with ease, with a slightly narrower chimney and some additional interesting research into the exhaust drawn into the headwind flow. This is all retrofittable of course. I really love originality but do we really have to live
for the next ump years with remaining problems from the past which are so extremely interesting to solve!
Kind regards
Jos Koopmans

 

This is fascinating. Many of us a are looking forward to 6023 being finally tested prior to mainline running. Surely when the draughting that Jos has designed for the King has been proven successful, an owning group will let him modify the front end of a Bulleid?